Dissemination and Vectors

Mistletoe dispersal is heavily reliant on birds, which eat the pseudoberries and inadvertently help the plant establish itself on new trees (Watson 2001). The pseudoberries are dispersed from February to May when songbirds fly back northwards (Wangerin 1937). Most important birds for mistletoe dispersal are the mistle thrush (Turdus viscivorus), fieldfare (Turdus pilaris), waxwing (Bombycilla garrula) and blackcap (Sylvia atricapilla). While the first three feed on the whole berry and excrete the “seed” without the berry skin, the blackcap feeds only on the skin of the berry and leaves the “seed” on a shoot nearby the mistletoe shrub. While sitting with the berry on a branch, it maintains the berry against the bark with its leg. It withdraws and swallows the external part of the pulp adhering to the teguments (Zuber 2004).

The approximate distance of dispersal by thrushes is 17 km and it is dependent on the length of the intestinal passage. The faster the digestion is, the shorter distance the seed achieves (von Tubeuf 1923). The long distance dispersal has to take place in another way, such as being stuck on the plumage or bill of birds and stripped off somewhere else (Wangerin 1937)